Of means multiplication and Is means equals. So 0.81x =405
X = 500
Answer:

Step-by-step explanation:

The number of students that are on the track team are 18.
The number of students that are on the baseball team are 15.
<h3>What are the linear equations that represent the question?</h3>
a + b = 33 equation 1
a - b = 3 equation 2
Where:
- a = number of students that are on the track team
- b = number of students that are on the baseball team
<h3>How many
students that are on the
baseball team?</h3>
Subtract equation 2 from equation 1
2b = 30
Divide both sides by 2
b = 30/2 = 15
<h3>How many
students that are on the track
team?</h3>
Subtract 15 from 33: 33 - 15 = 18
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The answers to the question are are the equations
y = 0.08x²-1.6x+13
y = 0.08(x-10)²+5
<h3>How to solve for the system of equations</h3>
David starts at (20, 13) and skates along a path that can be modeled by a quadratic function with a vertex at (10, 5).
Vertex form of quadratic function is
y = 
13 = a(x-10)²+5
let x = 20
a(20-10)²+5
13 = 100a + 5
take like terms
13 - 5 = 100a
8 = 100a
divide through by 100
a = 0.08
hence the equation would be
y = 0.08(x-10)²+5
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25 metres. Because 1/10th of a kilometre is a 100 metres. And four athletes divided by 100 metres is 25 metres.